Taumel gearing for manually adjusted hinge recliners employing single interengaging spur and ring gear elements are known in the art as disclosed in U.S. Pat. No. 3,401,979. Such hinges with manually actuated adjustment are not subject to high torque loading during adjustment since back pressure is normally relieved by the occupant in order to reduce manual torque applied to the adjustment knob. Accordingly, lateral separating forces and relative deflection of the taumel elements during adjustment is not a problem with the prior art manual taumel units. However, when such units are adapted with power drive of the taumel cam, the occupant may adjust the seat back inclination with his full back pressure applied which, particularly in the case of raising the back rest from a reclined position, may overload the taumel gearing having single taumel spur and ring gear elements.
The closest known prior art German Pat. No. 2,734,565, (U.S. Pat. No. 4,196,931) employs a manually actuated taumel cam for a seat bracket having no provision for forward dumping of the seat back and wherein sandwich taumel gearing drive between the bracket elements is effected through pin projections of a pair of spur gears through oversized bore holes in a bracket element accommodating eccentric displacement of the taumel spur gears. Additional background prior art includes West German Pat. Nos. 2,724,637, 2,733,488 and 2,808,889.